• 대한의생명과학회지
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• 제24권3호
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• pp.253-262
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• 2018

Platelets are activated at sites of vascular injury via several molecules, such as adenosine diphosphate, collagen and thrombin. Full platelet aggregation is absolutely essential for normal hemostasis. Moreover, this physiological event can trigger circulatory disorders, such as thrombosis, atherosclerosis, and cardiovascular disease. Therefore, platelet function inhibition is a promising approach in preventing platelet-mediated circulatory disease. Many studies reported the involvement of mitogen-activated protein kinases (MAPKs) signaling pathways in platelet functions. However, these studies were limited. Thus, we examined MAPK signaling pathways in human platelets using specific MAPK inhibitors, such as PD98059, SB203580, and SP600125. We observed that these inhibitors were involved in calcium mobilization and influx in human platelets. They also suppressed thrombin-induced ${\alpha}$- and ${\delta}$-granule release. These results suggest that PD98059, SB203580, and SP600125 exhibit $Ca^{2+}$ antagonistic effects.

• BMB Reports
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• 제42권6호
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• pp.380-386
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• 2009

In neurodegenerative diseases, such as Alzheimer' and Parkinson', microglial cell activation is thought to contribute to CNS injury by producing neurotoxic compounds. Prothrombin and kringle-2 increase levels of NO and the mRNA expression of iNOS, IL-1$\beta$, and TNF-$\alpha$ in microglial cells. In contrast, the human prothrombin kringle-2 derived peptide NSA9 inhibits NO release and the production of pro-inflammatory cytokines such as IL-1$\beta$, TNF-$\alpha$, and IL-6 in LPS-activated EOC2 microglia. In this study, we investigated the anti-inflammatory effects of NSA9 in human prothrombin- and kringle-2-stimulated EOC2 microglia. Treatment with 20-100 ${\mu}M$ of NSA9 attenuated both prothrombin- and kringle-2-induced microglial activation. NO production induced by MAPKs and NF-$\kappa$B was similarly reduced by inhibitors of ERK (PD98059), p38 (SB203580), NF-$\kappa$B (N-acetylcysteine), and NSA9. These results suggest that NSA9 acts independently as an inhibitor of microglial activation and that its effects in EOC2 microglia are not influenced by the presence of kringle-2.

• International Journal of Oral Biology
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• 제42권4호
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• pp.149-153
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• 2017

Cyclooxygenase-2 (COX-2)-mediated prostaglandin $E_2$ ($PGE_2$) plays a key role in development and progression of inflammatory responses and Porphyromonas gingivalis is a common endodontic pathogen. In this study, we investigated induction of COX-2 and $PGE_2$ by P. gingivalis in human dental pulp cells (HDPCs). P. gingivalis increased expression of COX-2, but not that of COX-1. Increased levels of $PGE_2$ were released from P. gingivalis-infected HDPCs and this $PGE_2$ increase was blocked by celecoxib, a selective COX-2 inhibitor. P. gingivalis activated all three types of mitogen-activated protein kinases (MAPKs). P. gingivalis-induced activation of nuclear $factor-{\kappa}B$ ($NF-{\kappa}B$) was demonstrated by the results of phosphorylation of $NF-{\kappa}B$ p65 and degradation of inhibitor of ${\kappa}B-{\alpha}$ ($I{\kappa}B-{\alpha}$). Pharmacological inhibition of each of the three types of MAPKs and $NF-{\kappa}B$ substantially attenuated P. gingivalis-induced $PGE_2$ production. These results suggest that P. gingivalis should promote endodontic inflammation by stimulating dental pulp cells to produce $PGE_2$.

• 한국식생활문화학회지
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• 제38권3호
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• pp.176-183
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• 2023

In this study, we investigated the effect of the extracts of Cyrtomium fortunei J.Sm. (CFJ) on lipopolysaccharide (LPS) induced inflammation in mouse BV-2 microglial cells. Nitric oxide (NO) production and cell viability were measured using the Griess reagent and the (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) (MTT) assay. Inflammatory cytokines were detected by quantitative polymerase chain reaction (qPCR) in BV-2 microglial cells with and without CFJ extracts. Subsequently, mitogen-activated protein kinases (MAPKs) and antioxidant markers were assessed by western blot analysis. It was found that the CFJ extract significantly decreased the production of pro-inflammatory cytokines (interleukin [IL]-6, tumor necrosis factor [TNF]-α, and IL-1β) and NO in BV-2 microglial cells that were stimulated with LPS. In addition, the expression levels of the phosphorylation of the MAPK family (p38, c-Jun N-terminal kinases [JNK], and extracellular-signal regulated kinase [ERK]) were reduced by CFJ. Also, treatment with CFJ significantly increased the activities of superoxide dismutase type 1(SOD1) and Catalase in BV-2 microglial cells. Our results indicate that CFJ has a potent suppressive effect on the pro-inflammatory responses of activated BV-2 microglia. Therefore, CFJ has the potential to be an effective treatment for neurodegenerative diseases, as it can inhibit the production of inflammatory mediators in activated BV-2 microglial cells.

• 한국축산식품학회지
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• 제44권3호
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• pp.699-709
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• 2024

Oxya chinensis sinuosa (OC) is a well-known edible insect. Several researches on the health benefits of OC consumption have been performed to date; however, their effect on eye health remains largely unknown. This study aimed to assess the protective effects of OC extracts on the oxidative stress on the retinal pigment epithelium (RPE) cells. Oxidative damage has been identified as one of the key regulatory factors in agerelated macular degeneration. H₂O₂-induced reactive oxygen species (ROS) production, a well-known oxidative stress factor, can cause cell death in retinal pigment epithelia cells. In this study, we found that three OC extracts effectively prevented H₂O₂-induced ROS production and subsequent death of ARPE-19 cells in a dose-dependent manner. In addition, the OC extracts inhibited the phosphorylation of mitogen-activated protein kinases including p38, JNK, and ERK. The OC extracts restored IκBα degradation induced by H₂O₂, indicating that OC extracts suppressed the activation of nuclear factorκB. Furthermore, the three OC extracts were shown to have antioxidant effects by upregulating the intracellular expression of key antioxidant proteins such as SOD, NQO, and HO-1. Here we demonstrated the antioxidant and anti-apoptotic effects of the OC extracts on ARPE-19, indicating their potential role in improving eye health. These results suggest that three OC extracts plays a critical role in oxidative stress-induced cell death protects in ARPE-19 cells.

• Biomolecules & Therapeutics
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• 제25권2호
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• pp.158-164
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• 2017

Methylglyoxal (MGO) is a highly reactive metabolite of glucose which is known to cause damage and induce apoptosis in endothelial cells. Endothelial cell damage is implicated in the progression of diabetes-associated complications and atherosclerosis. Hypericin, a naphthodianthrone isolated from Hypericum perforatum L. (St. John's Wort), is a potent and selective inhibitor of protein kinase C and is reported to reduce neuropathic pain. In this work, we investigated the protective effect of hypericin on MGO-induced apoptosis in human umbilical vein endothelial cells (HUVECs). Hypericin showed significant anti-apoptotic activity in MGO-treated HUVECs. Pretreatment with hypericin significantly inhibited MGO-induced changes in cell morphology, cell death, and production of intracellular reactive oxygen species. Hypericin prevented MGO-induced apoptosis in HUVECs by increasing Bcl-2 expression and decreasing Bax expression. MGO was found to activate mitogen-activated protein kinases (MAPKs). Pretreatment with hypericin strongly inhibited the activation of MAPKs, including P38, JNK, and ERK1/2. Interestingly, hypericin also inhibited the formation of AGEs. These findings suggest that hypericin may be an effective regulator of MGO-induced apoptosis. In conclusion, hypericin downregulated the formation of AGEs and ameliorated MGO-induced dysfunction in human endothelial cells.

• 동의생리병리학회지
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• 제35권5호
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• pp.177-184
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• 2021

The root bark of Morus alba L. (MA) used in traditional oriental medicine for the treatment of pulmonary diseases exerts various pharmacological activities including anticancer effects. In the current study, we investigated the effects of MA on the migration and invasion of colorectal carcinoma cells. Results from a transwell assay showed that the methylene chloride extract of MA (MEMA) suppressed the migration and invasion of HCT116 human colorectal carcinoma cells in a concentration-dependent manner. MEMA reduced both mRNA and protein levels of matrix metalloproteinase (MMP)-9, but did not suppress the expression of MMP-2 in HCT116 cells. As a molecular mechanism, MEMA inhibited the phosphorylation of mitogen-activated protein kinases (MAPKs), including ERK, JNK and p38, in a dose-dependent manner. In addition, MEMA dephosphorylated both Src and signal transducer and activator of transcription 3 (STAT3) in HCT116 cells. Taken together, we demonstrate that MEMA suppressed the migration and invasion capacity of HCT116 human colorectal cancer cells by downregulation of MMP-9 and inactivation of both MAPKs and Src/STAT3 signaling pathway.

• The Journal of Korean Physical Therapy
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• 제19권4호
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• pp.1-14
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• 2007

Background: It is generally accepted that skeletal muscle contraction is triggered by nerve impulse and intracellular $Ca^{2+}\;([Ca^{2+}]_i)$ released from intracellular $Ca^{2+}$ stores such as sarcoplasmic reticulum (SR). Specifically, this process, called excitation-contraction (E-C) coupling, takes place at intracellular junctions between the plasma membrane, the transverse (T) tubule L-type $Ca^{2+}$ channel (dihydropyridine-sensitive L-rype $Ca^{2+}$ channel, DHPR, also called tetrads), and the SR $Ca^{2+}$ release channel (ryanodine-sensitive $Ca^{2+}$ release channel, RyR, also called feet) of internal $Ca^{2+}$ stores in skeletal muscle cells. Furthermore, it has been reported that the $Ca^{2+-}$ dependent and -independent contraction determine the expression of skeletal muscle genes, thus providing a mechanism for tightly coupling the extent of muscle contraction to regulation of muscle plasticity-related excitation-transcription (E-T) coupling. Purpose: Expression and activity of plasticity-associated enzymes in gastrocnemius muscle strips have not been well studied, however. Methods: Therefore, in this study the expression and phosphorylation of E-C and E-T coupling-related mediators such as protein kinases, ROS(reactive oxygen species)- and apoptosis-related substances, and others in gastrocnemius muscles from rats was examined. Results: I found that expression and activity of MAPKs (mitogen-activated protein kinases, ERK1/2, p38MAPK, and SAPK/JNK), apoptotic proteins (cleaved caspase-3, cytochrome c, Ref-1, Bad), small GTP-binding proteins (RhoA and Cdc42), actin-binding protein (cofilin), PKC (protein kinase C) and $Ca^{2+}$ channel (transient receptor potential channel 6, TRPC6) was observed in rat gastrocnemius muscle strips. Conclusion: These results suggest that MAPKs, ROS- and apoptosis-related enzymes, cytoskeleton-regulated proteins, and $Ca^{2+}$ channel may in part functionally import in E-C and E-T coupling from rat skeletal muscles.

• BMB Reports
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• 제34권5호
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• pp.421-427
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• 2001

Osteoclasts, cells primarily involved in bone resorption, originate from the hematopoietic precursor cells of the monocyte/macrophage lineage and differentiate into multinucleated mature forms. We developed an in vitro osteoclast culture system using embryonic chicken bone marrow cells. This culture system can be utilized in studies on the differentiation and function of osteoclasts. Phosphatidylinositol 3-kinase (PI3-kinase) and mitogen-activated protein kinases (MAPKs) have been implicated in diverse cellular functions including proliferation, migration, and survival. Using the developed avian osteoclast culture system, we examined the involvement of these kinases in osteoclast differentiation by employing specific inhibitors of the kinases. We Found that the inhibition of the PI 3-kinase, p38, or ERK interfered with osteoclast formation, suggesting that the signaling pathways that involve these molecules participate in the process of chicken osteoclast differentiation.

• Molecules and Cells
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• 제40권10호
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• pp.706-713
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• 2017

Osteoclasts are bone-resorbing cells that are derived from hematopoietic precursor cells and require macrophage-colony stimulating factor and receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL) for their survival, proliferation, differentiation, and activation. The binding of RANKL to its receptor RANK triggers osteoclast precursors to differentiate into osteoclasts. This process depends on RANKL-RANK signaling, which is temporally regulated by various adaptor proteins and kinases. Here we summarize the current understanding of the mechanisms that regulate RANK signaling during osteoclastogenesis. In the early stage, RANK signaling is mediated by recruiting adaptor molecules such as tumor necrosis factor receptorassociated factor 6 (TRAF6), which leads to the activation of mitogen-activated protein kinases (MAPKs), and the transcription factors nuclear factor-${\kappa}B$ (NF-${\kappa}B$) and activator protein-1 (AP-1). Activated NF-${\kappa}B$ induces the nuclear factor of activated T-cells cytoplasmic 1 (NFATc1), which is the key osteoclastogenesis regulator. In the intermediate stage of signaling, the co-stimulatory signal induces $Ca^{2+}$ oscillation via activated phospholipase $C{\gamma}2$ ($PLC{\gamma}2$) together with c-Fos/AP-1, wherein $Ca^{2+}$ signaling facilitates the robust production of NFATc1. In the late stage of osteoclastogenesis, NFATc1 translocates into the nucleus where it induces numerous osteoclast-specific target genes that are responsible for cell fusion and function.